The present invention relates generally to airbags and more specifically to an apparatus for changing the trajectory of an inflating airbag to reduce the impact force of the airbag upon the windshield.
FIG. 1 diagrammatically illustrates a typical passenger compartment 20 of a vehicle showing opposing A-pillars 22, a windshield 24 and instrument panel 26. Situated on the top 28 surface of the instrument panel is a deployment door 30. The windshield is oriented relative to the top surface at an angle A which varies from about 20 degrees to 60 degrees. The door 30 is part of an instrument panel. Situated below the instrument panel is an airbag module 40 of known variety comprising: an airbag 42, an inflator 44 and a housing 46. The door 30 is capable of being separated from the rest of the instrument panel 26 upon deployment/inflation of airbag 42. Typically a plurality of stress risers or a weakened portion or tear seam 56 is fabricated in the instrument panel about the door 30. These stress risers/weakened portion/tear seam 56 are designed to rupture permitting the door to rotate toward the instrument panel, as illustrated in FIG. 2. As the door moves, the airbag 42 continues to inflate. This operation is designed to occur at the modest level of airbag internal pressure. The stress risers or tear seam 56 are designed to break at a modest internal airbag pressure to prevent propellant of the deployment for forcefully against the windshield.
Occasionally the weakened portions 56 do not break as designed, consequently, the airbag 42 will continue to inflate and press upon the underside of the door 30 with increasing force. When the weakened portions 56 finally break, the airbag 42 deploys outwardly with great force and the airbag 42 and door 30 are pushed against the windshield with an impulsive force F1 which can be sufficiently high to crack the windshield.
It is an object of the present invention to correct the deficiencies in the prior art.